# Copyright 2018-present Open Networking Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

""" XOSKafkaProducer """

import confluent_kafka

from xosconfig import Config
from multistructlog import create_logger
log = create_logger(Config().get('logging'))

kafka_producer = None


class XOSKafkaProducer:
    """ XOSKafkaProducer
        Wrapper to share Kafka Producer connection
    """

    @staticmethod
    def init():

        global kafka_producer

        if kafka_producer:
            raise Exception('XOSKafkaProducer already initialized')

        else:
            log.info('Connecting to Kafka with bootstrap servers: %s' %
                     Config.get('kafka_bootstrap_servers'))

            try:
                producer_config = {
                    'bootstrap.servers':
                        ','.join(Config.get('kafka_bootstrap_servers')),
                }

                kafka_producer = confluent_kafka.Producer(**producer_config)

                log.info('Connected to Kafka: %s' % kafka_producer)

            except confluent_kafka.KafkaError, e:
                log.exception("Kafka Error: %s" % e)

    @classmethod
    def produce(cls, topic, key, value):

        try:
            kafka_producer.produce(
                topic,
                value,
                key,
                callback=cls._kafka_delivery_callback
                )

            # see https://github.com/confluentinc/confluent-kafka-python/issues/16
            kafka_producer.poll(0)

        except confluent_kafka.KafkaError, err:
            log.exception("Kafka Error", err)

    def __del__(self):
       if kafka_producer is not None:
            kafka_producer.flush()

    @staticmethod
    def _kafka_delivery_callback(err, msg):
        if err:
            log.error('Message failed delivery: %s' % err)
        else:
            log.trace('Message delivered', message=msg)